Hoppered grain wagons or carts are well known for use in transporting granular material. The granular material is unloaded by gravity through a port in the bottom of the hopper, or by means of a conveyor mounted in the hopper and oriented to transfer the granular material to an exterior of the hopper.
Gravity dump wagons have conventionally been four-wheeled wagons. These four-wheeled wagons have predominantly used side discharge hoppers, where the bottom sump of the hopper is located on one side of the wagon such that the granular material flows out a port on the side approximately in line with the wheels. Such a configuration allows the operator to drive alongside a transfer conveyor and align the port with the transfer conveyor. Typically the transfer conveyor has a small intake hopper attached to the intake end thereof to collect and direct the granular material. The sump and port on the wagon are located high enough to clear such intake hoppers. Such side discharge four-wheeled wagons are disclosed in U.S. Pat. No. 2,827,204 to McCurdy and U.S. Pat. No. 6,095,616 to Grieshop.
In order to have the sump (the lowest part) of the hopper located on one side of the hopper, the sloping floor must extend from one side to the opposite side of the hopper. With a center discharge hopper, the sloping floors extend only about half way that distance, ie. from each side, and the ends, to the center. Center discharge hoppers thus have a greater capacity for the same height. Side discharge hoppers also carry more weight on the discharge side, and thus are not as stable as center discharge hoppers.
A four-wheeled wagon with a center discharge hopper is disclosed in U.S. Pat. No. 3,521,930 to Tucker. Four-wheeled wagons with mounted conveyors for discharge are also known, as for example in U.S. Pat. No. 5,615,990 to Grieshop and U.S. Pat. No. 4,646,942 to Kuhns where granular material from a side discharge hopper is directed into an auger conveyor. U.S. Pat. No. 3,391,812 to Heider discloses a side discharge four-wheeled wagon that allows for gravity discharge into the intake hopper of a transfer conveyor, or discharge through an auger conveyor.
The addition of a conveyor allows for unloading the granular material directly into another transport vehicle without the need for a transfer conveyor.
More recently two-wheeled carts with a conveyor discharge from a centrally located sump have become popular. These are typically large capacity carts carrying 500 bushels or more. The center sump provides maximum capacity for a given wall height, and improved stability over side discharge hoppers. Having only two wheels instead of four greatly simplifies the apparatus as well, since no steering mechanism is required. A steering mechanism strong enough to stand the stresses exerted by the weight of such a large capacity apparatus would be very costly and subject to wear and malfunction.
Examples of these two-wheeled carts are disclosed in U.S. Pat. No. 4,923,358 to Van Mill and U.S. Pat. No. 5,340,265 to Grieshop. Such two-wheeled carts were designed for towing in the field by a tractor to pick up grain from a combine harvester, commonly simply called a combine, and then transferring the grain directly into a truck for road transport to a storage location without the need for a transfer conveyor. There has thus been no provision made for gravity unloading the granular material into a transfer conveyor. A port is generally provided in the sump for cleaning granular material from the hopper, and the port may also be used for gravity dumping into a drive-over pit. The port is not, however, accessible from the side for moving the intake hopper of a transfer conveyor into position for receiving granular material from the port because the frame obstructs the area surrounding the port. On air-seeder carts, the conventional filling conveyor is oriented at a steep angle in order to reduce the length of conveyor required. This steep angle makes it even more difficult to move the intake hopper of such a filling conveyor into a position under the port to receive the contents of the container.
Conventional two-wheeled carts are thus limited in their utility. The unloading conveyor does not have sufficient reach to allow discharge directly into the top of an air-seeder cart. It is however not possible to unload into the intake hopper of a conventional filling conveyor on an air-seeder cart, except through the unloading conveyor. The height of the unloading conveyor discharge is such that, to avoid spillage during the fall into the intake hopper, a tube or the like must be positioned to receive the granular material from the conveyor discharge and direct same into the intake hopper. Such a process is impractical for repeated use, such as filling an air-seeder cart.
During planting two or more transport vehicles are often required to carry seed and fertilizer to the field. Different fertilizers, such as nitrogen, phosphate, potassium, sulfur, etc. may be required. Granular chemicals now are sometimes transported as bulk products rather than bagged. Air-seeder carts now often have three or more compartments to allow varying amounts of three or more products to be applied. Separate transport for each product is thus required, stretching the transport resources of the farmer.
To address this well recognized problem, and allow a wider range of vehicles to be used to carry required agricultural materials to an air-seeder, the filling conveyor of the air-seeder cart may be modified to reach under the port. Such a modification is disclosed in the laid open Canadian patent application number 2,257,048 of Lisafeld. That disclosed modification requires the addition of a universal joint and extended hopper to the standard filling conveyor. It would be an advantage to economically provide a more versatile transport vehicle that could instead be used with any conventional filling conveyor such as is presently found on the vast majority of air-seeder carts.